In this episode, the mysterious case surrounding the death of Yamaoka Takeshi is solved, which initially appeared to be a curse of Urashima Taro. Takeshi was found dead in a boat with white-dyed hair and a turtle shell armor.

Kogoro Mori reveals that Yamaoka Takeshi staged his own death to accuse Nishino Miku. Takeshi stole relics from the Urasawa Shrine, including a jewel-encrusted box with a poisonous frog, and built a workshop on the forbidden island to prepare his plan. His suicide was meant to accuse Miku of murder, out of despair over the loss of his brother Kazuo, similar to Urashima Taro, who could not bear the loneliness.

Although Miku was initially under suspicion, it becomes clear that she was actually responsible for the death of Kazuo. Togashi Hitomi, Takeshi's ex-girlfriend, observed Miku speaking with Kazuo's corpse, and was subsequently killed by Miku to force her silence. Hitomi left clues with chocolate syrup arrows, which led to the resolution.

Kazuo's corpse was found in the wall of Miku's open-air bath, which she referred to as the centerpiece of her ryokan. A chocolate syrup imprint on Miku's shoe confirmed her presence at the crime scene. When confronted, Miku attempts to flee, jumps into the sea, and is eventually arrested.

The episode ends with the arrest of Nishino Miku, after the police find Kazuo's corpse. Miku indirectly confesses her deeds when she refuses to go to prison, and instead flees, but fails.